Lubricating oil composition containing the neutralized reaction product of a phosphorus sulfide and sugar cane oil



Patented Sept. 21, 1954 UNITED STATES DFFICE LUBRICATING OIL COMPOSITION CONTAIN ING THE NEUTRALIZED REACTION PROD- UCT SUGAR CANE OIL OF A PHOSPHORUS SULFIDE AND No Drawing. Application February 15, 1952, Serial No. 271,866

Claims. 1

The present invention relates to lubricating oils, particularly those of the type known as crankcase oils for internal combustion engines, and more particularly to heavy duty oils for truck, bus, airplane and marine gasoline and diesel engines. More specifically, the present invention is concerned with improving agents or chemical additives for lubricating oils to increase the effective service life of engines using such oils under all types of operating conditions, and to methods of manufacturing the same.

These additives are oil soluble and act as detergents or anti-sludge agents to prevent the formation of hard sludge deposits due to sludge formation in the oil particularly at elevated temperatures and thereby maintain engine cleanliness. Additionally, these additives are effective to reduce oxidation or deterioration of the oil and inhibit or mitigate the normal corrosive action of such oils, or the decomposition products thereof, on metallic parts. Furthermore, these additives have the properties of increasing oiliness as well as improving the viscosity index, and depressing the pour point of mineral lubricating oils. 7

When conventional mineral lubricating oils are subjected to high operating temperatures,

especially for extended periods of time, as in heavy duty service, they tend to decompose and form complex and objectionable oxidation and decomposition products. Under the high temperature conditions prevailing in an engine, these hereinafter are accomplished by providing a hy-- drccarbon lubricating oil containing a new class decomposition products polymerize to form lacquer-like deposits on or between the moving parts of the engine, causing them to wear rapidly or to stick. Even larger quantities of polymerization products remain dispersed in the partly oxidized crankcase oil and are readily precipitated to form a sludge when the engine cools or when fresh oil is added to the engine. These precipitated sludges become caked on the heated metal surfaces and cut down the effective life of the engine by preventing proper functioning of the parts thereof, such as by hindering proper ring action, as well as causing bearing failures by blocking the passages of small diameter through which the lubricating oil normally flows to the bearings.

The principal objects of the present invention are to provide a lubricating oil composition capable of heavy duty service under varying operating conditions and which possesses excellent detergent properties, which is resistant to oxidation and sludge formation, is non-corrosive to metallic parts or alloy bearings, and which is free of additive compounds having detergent and other desirable properties, as above mentioned. The most desirable feature of this new class of additive compounds is noted in its ability to assist in preventing the deposition of hard deposits due to sludge formation in the oil, particularly at elevated temperatures.

We have found that sugar cane oil, either by itself or after a partial or complete saponification, may be reacted with phosphorus sulfides and that the neutralized resulting products of such reactions comprise excellent improvement agents for hydrocarbon lubricating oils and accomplish the desired results. These compounds are designated broadly herein as reaction products of sulfides of phosphorus and sugar cane oil, and salts thereof.

Sugar cane oil is the material, believed to be originally present in specialized cells throughout the cellular structure of sugar cane, which is obtained by solvent fractionation of the crude sugar cane wax extracted from the filter press muds of a sugar cane crushing plant. The chemical and physical characteristics of the sugar cane oil vary as to the source of supply and slightly different properties have been exhibited between sugar cane oils obtained from such sources as Cuba, Louisiana, South Africa, Brazil and India.

The invention is particularly applicable to the preparation of reaction products of sugar cane oil derived from Cuban sources and phosphorus sulfides but it is to be pointed out that of other sulfides has been found successful. For

example, other sulfides of phosphorus, namely,

' the pentasulfide, P285, and the hepatsulfide, P437,

have been satisfactorily employed.

In order to prepare the oil soluble lubricant additives of the present invention, sugar cane oil, either as such or in partially or completelysaponified form, may be mixed with the required amount of the selected sulfide of phosphorus and heated with constant agitation to an elevated temperature and blown with oxygen, whereupon a reaction will begin. This reaction is accomplished by the evolution of white fumes, presumably of oxides of phosphorus. lhe initial temperature of the reaction will naturally vary according to the specific sulfide of phosphorus selected and the chemical composition of the particular sugar cane oil and has been found to be approximately in the range of from 100 to 130 C.

This reaction is promoted or accelerated by the presence of the oxygen and the more intimate the contact between the oxygen and the sulfide of phosphorus and the sugar cane oil. the more effective is the promotion of the reaction. The oxygen may be supplied as such, or in the form of air or other free oxygen-containing gas which may be blown, bubbled into or otherwise passed through the mixture of reactants at the desired elevated temperature. This reaction is exothermic and, once it has begun, it' may be maintained at a desired temperature by the simple expedient of controlling the rate of passage of the free oxygen-containing gas through the mixture without the necessity of supplying any .additional heat from an external source. For the purposes of this invention, it has been found preferable to control the amount of oxygen in such a way as to provide a temperature in the range of from about 120 to 130 C. Higher temperatures such as up to 150 C. or higher have been employed with successful results but the control over the reaction in such a case is less and the uniformity of the resulting product decreases, due probably to high losses of'sulphur and phosphorus.

The conclusion of the reaction is indicated by a falling-E of the temperature of the reaction mixture and by the cessation of fuming, accompanied by an inability to increase such reaction temperature by increasing the rate of flow of oxygen through the mixture.

The employment of the oxygen during the reaction considerably shortens the reaction period and additionally accomplishes a more complete combination of the reactants, whereby the possi-- bility ofthe presence of free sulfides is minimized and a product having better odor and physical greater detail by the following specific examples. It should be understood, however, that although these examples may describe in particular detail some of the'specific features of the' invention they are given primarily for purposes 4 of illustration and the invention in its broader aspects is not to be construed as limited thereto.

Example 1 A specific analysis of one particular sample of Cuban sugar cane oil, selected primarily for purposes of illustration, indicates the following typical physical constants:

Sa'ponification number 156.0 Iodine number (Wijs) 85.8 Acid number 24.6

A chemical analysis indicated the approximate V composition of the sample of Cuban sugar cane oil to be as follows:

. Per cent Saturated acids 28.9 Unsaturated acids 28.9 Heptane insoluble acids 13.1 Hydrocarbons, alcohols 16.6 Sterols 6} Water soluble glyceririe', sugars 6:1

400 grams ofa Cuban sugar cane oil (to which 40 grams of butanol may be added as an antifoaming agent) was mixed with 1 2' grams of sodium hydroxide in 15-20' cc. of' Waterand the mixture is heated to 100-110 C. for 60 minutes under. arefiux condenser. This saponi fies approximately of" the sugar cane oil. 21 grams of zinc chloride (which is chemically equivalent in amountto the sodium hydroxide) in 30-35 cc. of water is then addedland the. mixture is heated for 15-30 minutes. This: converts all' the sodium salts to zinc salts. The mixture. is heated-to about -130 andavacuum is then applied in-order to strip outall volatilev matter.

The stripped and partially saponifi'ed' sugar caneoil is cooled to about 100 C1,.andl30' gms;

of phosphorus sesquisulfide in finely dividedform the cessationof the evolution of the white fu-mes toinsure completion of reaction- 400 grams. of SAE 10 lubricating oil-is thenaddeda-ndthereneedbe no filtration: nor other separation of: solidsat this-point;

T-he'solution comprising the partially. saponified sugar cane" oil-phosphorus sesquisu1fide=reaction product is y then neutralized with- 8- grams-- of zinc oxide suspended in 8 grams ofwater and 60-grams of barium-oxide (or thecorresponding amount ofbarium hydroxide) 1 or by any standard neutralizationprocedure. This usually-comprises adding-the zinc oxideand waterto thelubricating. oil solution of the acid andreacting at approximately. 100 C. for about 15-30 minutes; The

barium oxid (or the barium hydroxide) is then added, along with a small quantity of methanollif desired, and the heating is'continueduntil thesalt formation is complete. The batch isthenstrip ped of the final traces'of water and -methanolby' heating under a vacuum-which is applied gradu ally up to*29-3'0-inch'es of' mercury'and is filtered to remove the unreacted zinc oxide or barium oxide.

Example 2 1000 grams of sugar cane oil and 150 grams of butanol (used to prevent foaming and thickening during the saponification) were charged to a liter fiask fitted with a stirrer, thermometer, and a reflux condenser. 29 grams of sodium hydroxide was, dissolved in about its own weight of water and added. The reaction mixture was then heated to 100 C. and held at that temperature for 70 minutes. 49.5 grams of zinc chloride was then dissolved in an equal weight of water and added to the reaction mixture which was then stirred for an additional 30 minutes at approximately 90- 100 C. The reaction mixture was then stripped to 120 C. under a water-pump vacuum. The recovery of aqueous and non-aqueous distillates was approximately 58 grams and 158 grams respectively.

To the cooled stripped material, 75.2 grams of phosphorus sesquisulfide was added and the temperature raised to approximately 115? C. Air was then blown through the well-stirred reaction mixture at such a controlled rate so as to maintain the exothermic reaction at approximately 120- 125 C. After 60 minutes the exothermic reaction was over and the white fume evolution practically ceased. Air blowing was continued for an additional 30 minutes while maintaining the temperature of the reaction mixture at approximately 115-125 C. by the application of external heat.

At this point, 2000 grams of SAE lubricating oil, 150 grams of barium oxide and 75 grams of methanol were added. The reaction mixture was heated to methanol reflux and after -20 minutes became hydrogen sulfide free. After heating for an additional minutes, the resulting product was vacuum stripped to approximately 120 C. After adding 60 grams of High-Flow, the material was poured while hot into a one-gallon size precoated Sparkler filter. The filtration required 65 minutes, using a final pressure of approximately -35 lbs. and the cake was blown at 30 lb. pressure for 30 minutes. The yield of red-brown haze-free product was approximately 3059 grams.

Example 3 400 grams of sugar cane oil and 30 grams of finely divided phosphorus pentasulfide were mixed directly and heated to about 110-130 C. whereupon an exothermic reaction set in, which was substantially complete in approximately four hours. The remainder of the procedure followed that set forth in Example 1.

Example 4 4.5 kilograms of sugar cane oil, 256.5 grams of 50% NaOH and 450 grams of butanol were heated together with agitation to approximately 95 C. and held at that temperature for 80 minutes. 445.5 grams of 5% ZnClz was then added to the reaction mixture which was then stirred at 98 C. for an additional 15 minutes and then stripped under vacuum to 120 C. The stripped mixture was then cooled to 75 C. and 338.5 grams of phosphorus sesquisulfide were added and the temperature raised to 110 C. Air was then blown through the agitated reaction at such a rate that the exothermic reaction resulting therefrom increased the temperature to 130 C. The application of external heat was halted. After 80 minutes the white fumes of phosphorus oxides ceased but blowing of air was continued for 25 1 mixture to 100 C. and 1295 grams Ba(OH)2.8H2O

were added slowly and heating was continued until the salt formation was substantially complete. The material was then filtered and vacuum stripped. The yield was 8154 grams.

It is to be appreciated that although the preceding examples involve the use of basic compounds of barium and zinc, it is to be realized that other compounds containing various other reactive metal compounds may be used, preferably the other alkaline earth metals, magnesium, calcium and strontium. Among the various other metal salts which have been employed in carrying out the invention are those of the salt-forming radicals nickel, cobalt, chromium, aluminum, tin, and others.

The effectiveness of the above described compounds in promoting engine cleanliness, under conditions of severe service, is demonstrated by the following results obtained by subjecting an SAE No. 30 solvent refined Mid-Continent oil having an -95 viscosity index to a standard 25- hour'Lawson accelerated ring sticking test. The inhibitor used was zinc dihexyldithiophosphate, 50% in oil, and the particular detergent was a barium oxide neutralized reaction product of P4S3, and zinc oxide saponified crude sugar cane oil. a

These ratings, of course, refer to the usual Lawson system wherein 1 is the poorest rating and signifies heavy varnish or carbon deposits and 5 is a perfect rating and signifies no deposits and clean surfaces. The results of this test clearly show the superior detergent properties of our new lubricating additives.

The effectiveness of the above described compounds in depressing pour points of lubricating oils is demonstrated by the following results obtained by subjecting a Mid-Continent A-85 base oil having a pour point of 15 F. Two samples of a neutralized reaction product of phosphorus sesquisulfide and sugar cane oil (two different sources) were employed.

Composition: Pour point, F. Oil (control) 15 1% Sample A 10 1% Sample B 0 From the foregoing it is seen that we have provided novel detergent compositions suitable for use as improvement agents for hydrocarbon lubricating oils operative to assist in preventing the deposition of hard deposits 'due to sludge formation of the oil at elevated temperature. These compositions are further valuable as antioxidants, pour-point depressants and have the properties of increasing oiliness as well as improving extreme pressure characteristics and viscosity indices.

Although we have described but a few specific examples of our invention, we consider the case not to be limited thereby nor to the specific substances mentioned therein, but to include various other equivalent compounds of similar constitu- 7 tion as set forth in the claims appended hereto; It is understood that any suitable changes or variations may be made without departing from the spirit or scope of the inventive concept.

LA composition suitable for use as an improvement agent for hydrocarbon lubricating oils operative to assist in depressing the pour point of said hydrocarbon lubricating oil and preventing the deposition of hard deposits due to sludge formation in the oil comprising as its essential ingredient a neutralized reaction product res-ulting from chemically reacting a phosphorus sulfide with a member of the group consisting of sugar cane oil, partially saponified sugar cane oil and completely saponified sugar cane oil, and then neutralizing the product of such reaction with a member of the group consisting of metal oxides hydroxides, said sugar cane oil having a saponification number of approximately 156, an

iodine number of approximately 85.8 and an acid number of approximately 24.6.

2. A composition suitable for use as an improvement agent for hydrocarbon lubricating oils operative to assist in depressing the pour point of said hydrocarbon lubricating oil and preventing the deposition of hard deposits due to sludge formation in the oil' comprising as its essential ingredient a neutralized reaction product resulting from chemically reacting phosphorus sesquisulfide with a member of the group consisting of sugar cane oil, partially saponified sugar cane oil and completely saponified sugar cane oil in the presence of a free-oxygen containing gas and at a temperature to promote such a reaction, and neutralizing the product of such reaction with a member of the group consisting of metal oxides and hydroxides, said sugar cane oil having a. saponification number of approximately 156, an iodine number of approximately 85.8 and an acid number of approximately 24.6.

3. A lubricating oil composition comprising a predominating amount of a hydrocarbon lubricating oil and a minor amount of a detergent composition operative to assist in depressing the pour point of said hydrocarbon lubricating oils and preventing the deposition of hard deposits due to sludge formation in the oil, said detergent composition comprising as its essential ingredient a neutralized reaction product resulting from chemically reacting a phosphorus sulfide with a member of the group consisting of sugar cane oil, partially saponified sugarcane oil and completely saponified sugar cane oil, and then neutralizing the product of such reaction with a member of. the group consisting of metal oxides andhydroxides, said. sugar cane oil having a saponification number of approximately 156, an. iodine number of approximately 85.8 and an acid number of approximately 24.6.

4. A lubricating oil composition comprising a hydrocarbon lubricating oil having dissolved therein a detergent composition operative to assist in depressing the pour point of said hydrocarbon lubricating oil and preventing the deposition of hard deposits due to sludge formation in the oil, said detergent composition comprising as its .essential ingredient a neutralized reaction product resulting from chemically reacting phosphorus sesquisulfide with a member of the group consisting of sugar cane oil, partially saponified sugar cane oil and completely saponifi-ed sugar cane oil in the presence of a freeoxygen containing gas and at a temperature to promote such a reaction, and neutralizing the product of such reaction with a member of the group consisting of metal oxides and hydroxides, said sugar cane oil having a saponification number of approximately 156, an iodine number of approximately 85.8 and an acid number ofapproximately 24.6. I

5. A lubricating oil composition comprising a predominating amount of a hydrocarbon lubrieating oil and about 0.8% to about 8.0% by Weight of a detergent composition operative to assist in depressing the pour point of said hydrocarbon lubricating oil and preventing the deposition of hard deposits due to sludge formation in the oil, said detergent composition comprising as its essential ingredient a neutralized reaction product resulting from chemically reacting phosphorus sesquisulfide with a member of the group consisting of sugar cane oil, partially saponified sugar cane oil and completely saponified sugar cane oil in the presence of a free-oxygen contain ing gas and at a temperature to promote such a reaction, and neutralizing the product of such reaction With a member of the group consisting of metal oxides and hydroxides, said sugar cane oil having a saponification number of approximately 156, an iodine number of approximately 85.8 and an acid number of approximately 24.6.

References Cited in the file of this patent UNITED STATES PATENTS Number 7 Name Date 2,252,985 Rutherford Aug. 19, 1941 2,358,305 Cook Sept. 19, 1944 2,415,838 Musselman Feb. 18, 1947 2,419,325 Musselman Apr. 22, 1947 2,427,272 Fuller et al Sept. 9, 1947 2,582,958 Brennan et a1. Jan. 22, 1952 

1. A COMPOSITION SUITABLE FOR USE AS AN IMPROVEMENT AGENT FOR HYDROCARBON LUBRICATING OILS OPERATIVE TO ASSIST IN DEPRESSING THE POUR POINT OF SAID HYDROCARBON LUBRICATING OIL AND PREVENTING THE DEPOSITION OF HARD DEPOSITS DUE TO SLUDGE FORMATION IN THE OIL COMPRISING AS ITS ESSENTIAL INGREDIENT A NEUTRALIZED REACTION PORDUCT RESULTING FROM CHEMICALLY REACTING A PHOSPHORUS SULFIDE WITH A MEMBER OF THE GROUP CONSISTING OF SUGAR CANE OIL, PARTIALLY SAPONIFIDED SUGAR CANE OIL AND COMPLETELY SAPONIFIED SUGAR CANE OIL, AND THEN NEUTRALIIZING THE PRODUCT OF SUCH REACTION WITH A MEMBER OF THE GROUP CONSISTING OF METAL OXIDES AND HYDROXIDES, SAID SUGAR CANE OIL HAVING A SAPONIFICATION NUMBER OF APPROXIMATELY 156, AN IODINE MEMBER OF APPROXIMATELY 85.8 AND AN ACID NUMBER OF APPROXIMATELY 24.6. 